Brake-shoe grinding device



June 11, 1968 F. ATZBERGER 3,387,411

BRAKE-SHOE GRINDING DEVICE Filed June l5, 1965 2 Sheets-Sheet l 34 FIG.l.

ATTORNEY..

June 11, 1968 F. ATZBERGER BRAKE-SHOE GRINDING DEVICE 2 Sheets-SheetFiled June l5, 1965 w FIG. 3. 39w 33 F IG. 5.

INVENTOR FRANK ATZBERGER ATTORNEY.

United States Patent O 3,337,411 BRAKESHUE GlRlNDlNG Dill/ECE FrankAtzberger, 9'7-26 Sutphin Blvd.,

damaica, NSY. 11435 Filed lune 15, 1965, Ser. No. 464,019 Claims. (Cl.51-95) ABSTRACT OF THE DISCLOSURE A brake-shoe grinding device forrefinishing brake shoes as a workpiece, which comprises a frame having arecess and slide means are movable in the recess of the frame. Athreaded spindle is rotatably' but axially immovably mounted in thesli-de means, so that upon rotation of the spindle, the slide means isdisplaced. A bolt extends horizontally from the slide means and at leastone support means is secured to the bolt for movement in axial directionor" and rotation about the bolt. Grinding means supported for rotationare in substantially parallel relation to the bolt, and means foradjusting the distance between the grinding means and the support meansare arranged, the adjusting means include separately controllable coarseand line adjusting means and the threaded spindle constitutes the coarseadjusting means. The adjusting means include a hand wheel for moving theslide means along in axial direction of the threaded spindle, and meansare provided for biasing the slide means out of engagement with thegrinding means.

mma- The present invention relates to a device for grinding brakeshoes,particularly adapted to be used for brakes in automotive vehicles.

It is known that braking surfaces of brake-shoes re quite finishing fromtime to time in order to restore the exact cylindrical surfaces of thebrakeshoes.

As a rule, the refinishing of brake-shoes is done by mounting the sameonto the chuck of a lathe or similar machine tool, lfor rotation aboutits own axis. The worn surface to be reiinished is then subjected tosuccessive cutting operations of a roughing tool and a finishing tool,suitably secured to and carried by a turret-head, the latter beingsecured to and carried by the forward 'face of a shank. The latter isusually carried by a slide rest or the like, by which the tool is heldand traversed,

The necessary special lathes are available only in special shops. Thus,the refinishing or grinding of brake-shoes was hitherto a comparativelyexpensive procedure.

It is, therefore, one object of the present invention to provide adevice for grinding or refinishing brake-shoes, which is of extremelysimple construction and may be used in any gas station, small repairshop, or even a garage, without requiring a particular lathe.

It is another object of the present invention to provide a device forgrinding brake-shoes, wherein one or two brake-shoes are mounted onappropriate supporting brackets where they may be properly centered, acoarse and line adjusting means being provided for approaching thebrake-shoes to and removing them from the peripheiy of a rotatinggrinding cylinder.

It is yet a further object of the present invention to provide a devicein which the brake-shoe may be moved axially in addition to the movementtoward and away from the rotating grinder cylinder.

It is yet another object of the present invention to provide a device,wherein a relatively simple fine-adjusting means is provided by way ofan eccentric allowing, be-

ICC

sides coarse lateral movement of the brake-shoe before or during thegrinding operation.

With these and other objects in view which Will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawings, in which:

FIGURE 1 is a front elevation of the brake-shoe grinding device designedin accordance with the present invention;

FIG. 2 is a top plan View, partly in section, of the device disclosed inFIG. 1;

FIG. 3 is an elevation along the lines 3-3 of FlG. 2, parts being brokenaway for the purpose of better demonstration;

FIG. 4 is a section along the lines 4-4 of FG. 2; and

FIG, 5 is a front elevation of another embodiment of the device similarto that of FIG. 3.

Referring now to the drawings and in particular in FIGS. 1 and 2, thebrake-shoe grinding device comprises a frame 1, having a recess 2, inwhich a carriage or slide 3 is displaceably disposed. Conventionalmeans, like tongues and grooves, or dovetail-shaped guides may beprovided as guiding means for the slide 3. A horizontally disposed bolt4 is journaled in the slide 3 and has a for wardly protruding,rounded-olf end which receives a bracket 5. The latter carries twovertically spaced apart bars 6 and 7, and the ends of the bars 6 and '7have secured thereto adjustable brake-shoe supports 8. Releasablesecuring means, as thumb or knurled screws 9 are used between the bars 6and 7 and the supports ti, so as to adjust the distance of the latterfrom the longitudinal axis of the bolt 4.

Th-e arcuate brake-shoes to be ground on the device according to thepresent invention are shown at 10. Fastening bolts .11 securebrake-shoes 1d to the supports 3. One of the supports S, eg., the oneshown on the righthand side of FIGS. l and 2, has a forwardly protrudinghandle 12 attached thereto for manually turning the brake-shoes 1l) withtheir supporting structure, as will be more clearly set forth below.

The brake-shoe grinding device is operated by an eicetric motor 13 whichdrives a sand grinder 14 by way of appropriate pulleys and a belt, thedrive being generally designated 15. The grinder 14 is secured to ashaft 16 which carries also a bladed fan 17 adapted to remove the groundand abrasive particles within the frame of the device. A conventionalelectric switch 1li controls the operation of the electric motor 13.

The bolt 4 jointly with the brake-shoes 1G mounted thereon can be movedcloser or farther away from the grinder .14. To this end, coarse andfine adjusting means for such movement are provided. In order to bringabout the coarse adjustment, a threaded spindle .19 is provided, whichpasses through a complementary threaded bore of the carriage or slide 3;at its outer free end, the threaded spindle 19 is equipped with a handwheel 2li. The hand wheel 20 may be provided with graduations 21. Anindex or pointer 22 is provided on the frame 1, as shown in FIG. 2 ofthe drawings.

Referring now again to the drawings, and in particular to FIG. 4, asecond slide 23 is provided which has a bore 24 for the passage of thespindle 19. A set screw 25 engages an annular groove 26 of the spindle19, so that the slide 23 cannot move in axial direction of the spindle19. As long as the latter is stationary, manual rotation of the handwheel 20 will displace the carriage 3 in one direction or the other,bringing the brake-shoes 9 closer or away from the grinder 14.

In order to bring about the afore-mentioned fine adjustment, the frame Ihas another recess 27, in which the slide 23 can be displaced withincertain limits (see FIGS. 3 and 4). Conventional guide means may, ofcourse, be provided, as schematically shown in FIG. 4 between the slide23 and the frame il.

A `link 2S is pivoted at one end in the slide 23 at a ful'crum 29 (FIG.3); the other end of the link 23 can be acted upon by an eccentricmechanism constructed as follows: A bushing 34) is provided in the frame1, in which shaft stub 3l having an angularly bent front portionparallel with its rear portion is rotatably received in the bushing 30.An eccentric dise 32 is secured to the front portion to which disc 32,in turn, is attached the other end of the link 28. A hand lever 33projects upwardiy from the disc 32, which lever can swing in bothdirections, as indicated in FIG, 1 by an arrow 3d.

When actuating the lever 33, the shaft stub 31 will perform acorresponding small rotation with the disc 32, so as to displace theattached link 28, the slide 23 and consenquently the spindle I9 whichholds the carriage 3 with the brake-shoes it). A compression spring 35is disposed between the slide 23 and a frame projection 36 for urgingthe slide 23 and thereby the spindle 19 away from the grinder cylinder1d, against the grinder-engaging movement of the lever 33 to theleft-hand side, as viewed in the drawings.

By the arrangement just described, a ne adjustment is brought aboutbetween the brake-shoes l and the grinder ld. The top of the machineframe i has a ne graduation 37, while an index 33 is attached to thecarriage 3, supplementing thereby the coarse indication provided by thehand wheel 2t?. These setting means are particularly shown in FIG. 2,where the coarse indicators 2i and 22, as well as the fine indicators 37and 38 are clearly shown.

An adjustable stop member 39 secured to the front wall of the frame l isdisclosed, which limits the leftward swinging movement of the hand lever33, as viewed in FIGS. l-3.

As a matter of example, the stop member may be constituted by a boltslidable in an arcuate slot of the frame l and adapted to be retained inany position, e.g., by means of a threaded nut or a counter-nut behindthe front wall (not shown).

The stop member 39 is adapted to limit the iine adjustment towards thegrinder 14, While movement in the opposite direction, away from thegrinder is not limited.

A forwardly protruding portion 40 of the frame 1 (FIG. 2), which lodgesthe grinder 14 is equipped with a hinged iiap di, which normally abutsagainst the outer surface of the brake-shoe facing the grinder I4. Thepreferred direction of rotation of the spindle system 4 with thebrakeshoes 10 being in clockwise direction, as indicated by the arrow 42(FIG. 1), relative to the similarly clockwise direction of rotation ofthe grinder 14, indicated by the arrow 43, the flap 41 will prevent thebrake-shoes l@ from being rotated in the wrong direction, that iscounterclockwise. As shown in FIG. 2 the flap 41 is of a length to coverthe entire engaging surface of the rotating grinder lid, underneath anappropriate recess of the frame portion riti, so that the flap 41 alsoserves the purpose of directing the ground and removed metal andabrasive particles inside the frame portion 40 (see also FIG. l),regardless of the axial position of the brakeshoes 1t) with respect tothe spindle 4, rather than to allow these particles to drop underneaththe line of engagement between the treated brake-shoe i0 and the grinder14. The mentioned fan I7 contributes to the removal of the ground metaland abrasive particles.

The brake-shoe grinding device is operated in the following manner: Oneor two brake-shoes 1t) are secured onto the support 8 by releasing andthen tightening the fastening bolts It?. The radial distance of thesupport 8 from the longitudinal axis of the spindle 4 has, by means ofthe screws 9, been previously adjusted. Upon starting the motor 13 byoperation of the switch 1S, the operator holds on to the handle l2 withone hand, while operating the coarse adjustment (handwheel 2li) with theother hand.

It is also possible to preset the coarse adjustment with the hand wheel21 and to operate the fine adjusting lever 33. During the grindingoperation, while slowly manually rotating the brake-shoes it@ in thedirection of the arrow 42 by means of handle l2, the bracket 5 is alsomovable in axial direction, as shown by the double-headed arrow 44 inFIG. 2. This axial setting of the bracket 5 brings about a uniformgrinding of the entire width of the brakeshoes, and the operation withthe entire working surface of the grinder i4.

Upon completion of the grinding of the brake-shoe or shoes which havebeen attached to the support, the latter is moved away from the grinder14 by turning the hand wheel 2t) in opposite direction. A new set ofbrakeshoes is then fastened to the support, so as to repeat thereafterthe grinding procedure.

FIG. 5 shows a modied embodiment of the arrangement, wherein a carriage3a is movable within the recess 2 of the frame l. A stud ia isadjustably attached to the carriage 3a by means of a shaft sleeve orstub Sia, fitted into a recess of the carriage 3a, and having itself aneccentric bore yfor the stud da. A hand lever 33a is attached to thesleeve 31E-ra, so as to rotate the same slightly, causing thereby alateral shifting of the stud 4a with respect t0 the carriage 3a. Thus,the fine adjusting means of FIG. 5 acts on the stud 4a by slightlydisplacing it laterally, in one direction or the other, while the coarseadjustment by the hand wheel 20 moves the slide 3a in the recess 2, ashas been described previously for the first embodiment. The operation ofthe modified device is essentially the same as described before. Asupporting bushing 45, secured to the frame ll for the threaded spindleI9 is disclosed, allowing free longitudinal sliding of the spindlemovement, while sufliciently supporting it at its end close to the handwheel 243.

While I have disclosed several embodiments of the present invention, itis to be understood that these embodiments are given by example only andnot in a limiting sense, the scope of the present invention beingdetermined by the objects and the claims.

I claim:

1. A brake-shoe grinding device for refinishing brakeshoes as aworkpiece, comprising a frame having a recess, slide means movable insaid recess of said frame,

a threaded spindle rotatably but axially immovably mounted in said slidemeans, so that upon rotation of said spindle, said slide means isdisplaced,

a bolt extending horizontally from said slide means,

at least one support means secured to said bolt for movement in axialdirection of and rotation about said bolt,

grinding means supported for rotation in substantially parallel relationto said bolt,

means for adjusting the distance between said grinding means and saidsupport means,

said adjusting means including separately controllable coarse and fineadjusting means,

said threaded spindle constituting said coarse adjustlng means,

said adjusting means including a hand wheel for moving said slide meansalong in axial direction of said threaded spindle, and

means for biasing said slide means out of engagement with said grindingmeans.

2. The grinding device, as set forth in claim 1, wherein said neadjusting means includes movable bearing means for a portion of saidcoarse adjusting means,

an eccentric stub shaft pivotable in said frame and operativelyconnected to said bearing means, and

actuating means for pivoting said stub shaft `in either direction,thereby moving said slide means jointly with said threaded spindle. 3.The grinding device, as set forth in claim 2, wherein said bearing meanscomprises a second slide means movable with said first mentioned slidemeans and said threaded spindle, and a link is operatively connectingsaid stub shaft with said second slide means so that upon operation ofsaid actuating means said second slide means is adjusted. 4. Thegrinding device, as set forth in claim 2, which includes adjustable stopmeans for said actuating means, for

limiting its movement in at least one direction. 5. The grinding device,as set forth in claim 4, which includes a hinged ap attached to saidframe in a peripheral region of said brake-shoe, for frictionallypreventing rotation of said brake-shoe against the edge of said ap.

References Cited UN'iTED STATES PATENTS 1,952,130 3/1934 Harrison 51-217X 2,225,806 2/1940 Stone 51--217 X 2,345,161 3/1944 Thomason 51-217 X2,604,739 7/1952 Evans 51--217 X 2,715,799 8/1955 Billeter 51-962,789,404 4/1957 Downing 51-273 3,022,610 2/1962 Barrett 51-96 3,025,6453/1962 Bonkowski 51-105 3,060, 644 10/ 1962 Wisti 51-96 ROBERT C.RORDON, Primary Examiner.

LESTER M. SWINGLE, Examiner.

D. G. KELLY, Assistant Examiner.

